The present invention relates to a multimode mobile telephone apparatus having a structure that a plurality of portable terminals adapted to different communication systems are integrated to one multimode mobile telephone apparatus.
FIG. 2 is a diagram showing an example of the structure of a usual single-mode portable terminal. As shown in FIG. 2, a single-mode portable terminal 6, which is so-called a "mobile telephone", usually incorporates a wireless communication means 41 for establishing communication with a network so that communication with a base station 3 is established, a transmitter 27 and a receiver 26 for performing a conversation, a key pad 25 for inputting a telephone number, a display unit 24 for displaying a telephone number and so forth, a control circuit 22 incorporating a CPU (not shown) for controlling the foregoing elements and a memory 23 in which programs are stored.
A so-called man-machine interface (hereinafter called a "MMI") section which is operated by a user and supplying information to the user is constituted by the transmitter 27, the receiver 26, the key pad 25, the display unit 24, the control circuit 22 for executing the MMI program and the memory 23 in which the MMI program is stored. Note that the control circuit 22 and the memory 23 are not provided for only the MMI and arranged such that the programs for controlling the wireless communication means 41 for establishing communication with a network and the like are stored so as to be executed by the CPU. Although a portion of structures is formed such that the above-mentioned key pad 25 and the display unit 24 provided for the MMI section are realized by a display unit having a touch panel, description will now be performed about the structure incorporating the key pad 25 and the display unit 24.
There is a variety of communication systems for the mobile telephones which have variety of characteristics. For example, the PDC system exhibits a high coverage ratio of population and permits communication even during high speed movement of the user. The PHS system suffering from its narrow service area exhibits a low charge and performance of high-speed data communication. A satellite mobile telephone is able to establish communication in the mountains and on the sea area. To create a satisfactory service by combining the foregoing characteristics, a so-called multimode portable terminal 7 corresponding to a plurality of methods as shown in FIG. 3 has been developed and put into practical use. An example of the foregoing terminal is disclosed in Japanese Patent Laid-Open No 3-1621.
The mobile telephone, the service of which has been varied and the function of which has been improved, must improve its operability and ease of use for a user. When ease of use is improved, a larger number of keys, a wider display screen and a more complicated program are required. Therefore, the key pad 25, the display unit 24 and the memory 23 are enlarged or increased. Since the enlargement of the size of the MMI section, however, enlarges the overall size and overall weight of the portable terminal, the portability which is the most important requirement for the portable terminal deteriorates. A wireless telephone apparatus disclosed in Japanese Patent Laid-Open No. 7-50877 has a structure to solve the foregoing fact such that the portion including the transmitter and the receiver is separated from the other portion. The foregoing portion including the transmitter and the receiver and the other portion are connected to each other through a second wireless circuit. Thus, only the transmitter and the receiver portion having small size and light weight are made to be portable. Thus, the portability can be improved.
In general, development of the multimode portable terminal 7, however, is considerably difficult as compared with development of the single-mode portable terminal 6. As shown in FIG. 3, the multimode portable terminal 7 must incorporate a plurality of wireless communication means 41a and 41b for establishing communication with a network corresponding to supported communication methods in the case thereof. The wireless communication means 41a and 41b for establishing communication with a network accommodated adjacent to each other frequently encounters deterioration in the performance owing to interference. To solve the foregoing fact, the shielding function for preventing interference must be enhanced, the physical distance must be maintained and sophisticated control of the wireless communication means 41a and 41b for establishing communication with a network is required. As a result, there arises problems in that the size of the case and the weight of the same are enlarged, a period of time required to develop the control program is elongated, the man-hours is increased and resulting enlargement of the cost cannot be prevented.
In general, development of the MMI for the multimode portable terminal 7 requires a larger number of man-hours as compared with the MMI for the single-mode portable terminal 6. The reason for this lies in that the difference in the method causes the specifications of the MMI (for example, the number of keys, a method of invoking the menu, the number of digits of the telephone numbers which must be received and the name of the service) to usually be different. The foregoing differences do not raise a critical problem when a user selects the single-mode portable terminal 6 from a plurality of the single-mode portable terminals 6 adapted to a plurality of methods. The reason for this lies in that the user is able to recognize the difference in the specification as the difference in the terminal. Therefore, the user is convinced of performing operations of the different terminals corresponding to the different specifications.
Since the multimode portable terminal 7 is only one portable terminal from a viewpoint of a user, it is difficult to change a mind to select a single-mode portable terminal 6 from a plurality of the single-mode portable terminals 6. Therefore, in a case of a conventional structure where the specifications of the MMI for the variety of single-mode portable terminals 6 are simply added, a degree of unification of specifications is unsatisfactory for a user. Therefore, the specifications are incomprehensible, causing the ease of operation to considerably deteriorate. Hence it follows that development of the multimode portable terminal 7 must be performed such that following of the specification of the single-mode portable terminal 6 is not performed. The MMI portion must newly designed and developed such that all of the functions of the single-mode portable terminals 6 are included in the MMI portion. Therefore, a period of time required to develop the program for the MMI is elongated and the man-hours is increased undesirably. As the methods which must be combined increase, the foregoing problem becomes more critical.
As described above, the conventional multimode portable terminal 7 encounters excessive enlargement of the size of the case and the weight. Thus, the portability deteriorates. Moreover, integration of a plurality of communication methods into one terminal encounters a multiplicity of technical problems. The wireless telephone apparatus disclosed in Japanese Patent Laid-Open No. 7-50877 has the structure that the transmitter and the receiver are formed into the independent portion to improve the portability. The foregoing technique is, however, developed for the single-mode portable terminal 6. Therefore, any consideration is not made about switching of the method required for the multimode portable terminal 7.